Interval timer



i@ 5, fav@ 11 E 8 ,Zu/ 2, n Hf# 3 @d V /,ru Wk/edn f/M? /Ma m M f 5mm/WJ ST8 Mw EMM SEd Oct. 25, 1966 ldrive-out begins.

United States Patent G 3,281,548 ENTERVAL TIMER Walter J. Sears,Cupertino, Calif., .and Samuel Polonsky,

Medway, Mass., assignors to General Electric Company, a corporation ofNew Yori:

Filed May 8, 1964, Ser. No. 366,106 6 Claims. (Cl. 20G-38) Thisinvention relates to an all-purpose interval timer and, moreparticularly, to a unique timer mechanism which enables a single knob tocontrol manual on-oif operations in addition to timed-on and timed-offoperations.

In addition to the conventional manual -on-oif switch operations, it isoften desirable to be able to set a switch to either a timed-off or atimed-on position for a specified time after which the switch isautomatically actuated to the opposite position. Timed-off is generallyapplied to the situation where the switch is set at an open circuitposition and remains there for a specified time after which the switchis automatically actuated to a closed circuit position where it remainsuntil manually reset. Timedon applies to the opposite sequence.

Conventional timers provide single-purpose timed-on or timed-offoperations but the prior art has not heretofore produced a simple,all-purpose timer in which a single control knob may be used to set thetimer for manual on-off operation in addition to automatically timed-onand timed-off operations.

It is therefore an object of this invention to provide an all-purposeinterval timer having a plurality of timing operations.

Another object of this invention is to provide an interval timer whereina single switch is used for manual-on, manual-off, timed-on, andtimed-off operations.

A further object is to provide an interval timer which employs a simplebut unique mechanism for rapidly actuating a single switch for bothtimed and manual operations.

Further objects and advantages will become apparent as the followingdescription proceeds and the features of novelty are pointed out in theclaims annexed to and forming part of this specification.

In carrying out this invention in one form thereof, a single switch isactuated by a cam and a cam follower or actuating rod. The cam and adriven member having internal and external gear sectors thereon arepositioned in co-axial alignment on a set shaft. A control knob isattached to the set shaft for rotating the driven member and the cam formanual on-off operation and for engaging the external and internal gearsectors with a unidirectional driver pinion to effect 'timed on-oiiroperation. When the control knob is set at the manual-on or manual-offpositions, a spring engages a projection from the rotating mechanism andmaintains the gear sectors out of engagement with the unidirectionaldriver pinion while the cam maintains the switch in a closed or an opencircuit position, respectively. When the control knob is set to eitherthe timed-on or the timed-off positions, the unidirectional driverpinion meshes with either the external gear sector or the internal gearsector on the driven member and During drive-out, the switch ismaintained in an open or closed circuit position until the switch isactuated by the rotating cam to the opposite position, .at which timethe gear sector is disengaged from the unidirectional driver pinion.Since engagement between the unidirectional driver pinion and the gearsector has been discontinued, the switch remains in either an open orclosed circuit position until manually reset.

For a better understanding of the invention, reference is made to theaccompanying drawing in which:

FIG. 1 is a front view of the timer with the base plate ICC removedshowing the mechanism in manual-on position;

FIG. 2 is similar to FIG. 1 but shows the mechanism in timed-offposition;

FIG. 3 is similar to FIGS. l and 2 but shows the mechanism in thetimed-on position;

FIG. 4 is an end view of the timer showing the continuous driver motorand the conventional gearing used to drive the unidirectional driverpinion gear;

FIG. 5 is a perspective of the set shaft, cam, and the driven member.

Referring to FIGS. 1 and 2, the illustrated timer includes a switch 1mounted between two plates 2a and 2b. The switch 1 includes a pair ofspaced contacts 3a and 3b mounted on a contact-carrying arm 4. A movablecontact 5 is disposed therebetween on a movable contact-carrying arm 6.Engagement between the movable contact 5 and either of the contacts 3aor 3b closes a circuit. The movable contact 5 is actuated by a camfollower 7. The movable contact-carrying arm 6 engages the cam follower7 and yieldably forces the follower 7 into engagement with a rotatablecam 8. The follower may also be forced into engagement with the cam by aspring or other suitable means. The cam 8 is mounted on a set shaft 9for rotation with a driven member 11 through a loose tongue and slotengagement 22, as illustrated in FIG. 5. Rotation of the set shaft 9 andthe cam 8 actuates the switch between closed circuit and open circuitpositions.

In order to achieve a variety of switching operations, it is desirableto be able to automatically and manually rotate the switch actuatingmechanism in both directions. The set shaft 9 may be rotated by a knob23 for manually actuating the switch 1 to an open or closed position.The set shaft 9 is also arranged for timed rotation by a continuouscounterclockwise rotating driver pinion 10 for automatically actuatingthe switch to an open or closed circuit position after a predeterminedtime interval. Timed rotation of the set shaft 9 and the cam 8 isachieved by lselectively engaging the driver pinion 10 with the drivenmember 11 which is secured for rotation with the set shaft 9 asindicated in FIG. 5.

The driven member 11 has an external gear sector 12 for selectiveengagement with the driver pinion 10 on one side thereof to rotate thedriven member 11 in a clockwise direction. A radially disposed arm 13projects from the driven member 11 and extends beyond the radius of theexternal gear sector 12. A circumferential extension 14 from theradially extending arm 13 has a plurality of gear teeth comprising aninternal gear sector 15 on the radially inwardly disposed surfacethereof. The internal gear sector 15 `selectively engages the oppositeside of the driver pinion 10 and rotates the driven member 11 in acounterclockwise direction. Since the driver pinion 10 is continuouslyrotated in a counterclockwise direction by a motor 20 and a gear train21 as'shown in FIG. 4, suitable clutch means (not shown) are employed inthe gear train 21 to allow for manual engagement of the gear sectorswith the driver pinion during which time the driver pinion is forced torotate opposite to its normal continuous direction of rotation.

AThe external gear sector 12 and the internal gear sector 15 areangularly displaced on the driven member 11 with a gap 24 therebetween.The driver pinion 10 rotates the driven member 11 by engaging the gearsectors 12 and 1S. The driver pinion 10 tends to drive the gear sectorsout of engagement therewith, thereby positioning the gap 24 adjacent thedriver pinion 10. By employing a driven member having both external andinternal gear sectors selectively engageable with a unidirectionaldriver pinion, it is possible to achieve bidirectional rotation which,when applied to a cam member, may be used to actuate a switch to avariety of timed opera-tions.

The variety of operations contemplated by this invention includetimed-on, timed-off, manual-on, and manualolf. To actuate the switch 1during the four above-mentioned operations, the cam member 8 isemployed. The driven member 11 operates to rotate the cam lt! and toactuate the switch through the cam'follower 7. The cam 8 has a pluralityof major earn surfaces, namely, a timedopen circuit position surface 8a,a closed circuit position surface 8b, a timed-closed circuit positionsurface 8c, and an lopen circuit position surface 8d. The major camsurfaces have transition cam surfaces 25 therebetween. Actuation occurswhen the cam follower engages the transition surfaces 25 between themajor cam surfaces. If the cam were to move at its normally slow ratewhile the follower engages the transition surfaces 25, the switch wouldbe actuated slowly and arcing might occur. To Iaccelerate switchactuation and to obviate the necessity of using a snap-action switch,the cam 8 is floatingly mounted on t-he set shaft 9 to enable relativerotation between the cam and set shaft. The loose tongue and slotengagement 22 between the cam 8 and the driven member 11 permits a smalldegree of relative rotation between the cam and driven member. The looseengagement enables the cam 8 to be rapidly rotated relative to thedriven member 11 through a small angle by the cam follower 7 when thefollower 7 engages the transition surfaces 25. The follower 7 isyieldably Iforced -against the cam 3 by the movable contact carrying arm6 to assist the rapid rotation of the cam 8 during switch actuation.

The set .shaft may be lmanually setto maintain the switch in either amanual open or a manual closed circuit posh tion. A spring an-d ldetentmechanism is employed to maintain the set shaft in either manualposition. The mechanism includes a projection 17 from the Idriven memAber 11 having an open circuit detent 18 and a closed circuit detent `19disposed therein. A spring 16 is arranged between the plates 2a and 2band projects into the path of rotation of the projection 17. The spring16 and provjection `17 are arranged so that either detent may beselectively engaged with the spring to releasably secure the set shaftfrom rotation.

In order to clearly appreciate the physical relationship between thefour surfaces of the cam 8, the gear sectors and the gap there-betweenon the driven member 11, and the driver pinion during the variousoperations, each operation will be discussed separately.

Timed-open circuit operation F or timed-open circuit operation, thedriven member 11 is manually rotated clockwise by the con-trol knob 23until the internal gear sector is rotated into meshed engagement withthe driver pinion 10. After the manual setting force has been released,drive-out begins for the timed-open circuit operation and the driverpinion 10 rotates the driven member 11 in a counterclockwise direction.The time during which the driven member 11 is rotated `depends upon theproportion of the internal gear sector 15 through which the driverpinion 10 must -advance before the gap 24 between the gear sectors ispositioned f adjacent the -driver pinion 10 and meshed engagement isterminated. The timed-open circuit position surface 8a of the cam 8 isangularly arranged .relative to the driven member 11 so that the camfollower 7 engages the cam `surface 8a only when the driver pinion 10 isin meshed engagement with the internal gear sector 15 as indicated inFIG. 2. While the cam follower 7 engages the cam surface 8a, the movablecontact 5 is maintained out of engagement with the contacts 3a and 3band the switch is maintained in an open circuit position.

The closed circui-t position surface 8b of the cam 8 is disposedadjacent the cam surface Sa and angularly arranged relative to thedriven member 11 so that the cam follower 7 begins to contact the camsurface 8b at the end of the timed-open circuit drive-out, at which timethe switch 1 is actuated to a closed circuit position. Actuation occurswhen the cam follower 7 engages the transition surface 25 between thecam surfaces 8a and 8b. The force exerted by the follower 7 on thetransition surface 25 rapidly rotates the cam 8 through the loose tongueand slot e-ngagement 22. The rapid cam rotation accelerates switchactuation and avoids the necessity of using a snap-action switch. At theend of timed-open circuit drive-out, the driver pinion 10 has rotatedthe driven member 11 so that the gap 24 between the gear sectors 12 and15 is positioned adjacent the driver pinion 10, thus causingr the drivenmember 11 and the cam 3 to stop rotating. Since rotation of the cam hasstopped, the switch is maintained in a closed circuit position untilmanually reset.

Timed-closed circuit operation IFor timed-closed circuit operation t-hedriven member 11 is manually rotated counterclockwise by the controlknob 23 until the external gear sector 12 is rotated into meshedengagement with the driver pinion 10. After the manu-al setting forcehas` been released, drive-out begins for the timed-closed circuitoperation and the driver pinion 10` rotates the driven member 11 in aclockwise direction. The time during which the driven member 11 isrotated depends upon the proportion of the external gear sector 12through which the driver pinion 10 must advance before the gap 24between the gear sectors is positioned adjacent the driver pinion 10 andthe meshed engagement is terminated. The timed-closed circuit positionsurface 8c of the cam S is angularly arranged relative -to the drivenmember 11 so that the cam follower 7 engages the cam surface 8c onlywhen the driver pinion 10 is in meshed engagement with the external gearsect/or 12 as illustrated in FIG. 3.

The op-en circuit position surface 8d of the cam 8` is angularlyarranged relative to the driven member 11 so -that the cam surface 8d isrotated into engagement with the cam follower '7 at the end oftimed-closed circuit drive-out, a-t which time the cam `surface Sdactuates the switch to an open circuit position. Switch actuation fromthe timed-closed to open cir-cuit position is -accelerated by the rapidcam rotation relative to the driven member by means of the loose tongueand slot engagement 22. At the end of timed-closed circuit `drive-out,the gap 24 between the gear sectors 12 and 1S is positioned adjacent thedriver pinion 10 and the driven member 11 stops rotating. Since thedriver pinion 10 is no longer meshed with the drive-n member 11, theswitch is maintained in an open circuit position until manually reset.

Manual closed-circuit operation At the end of the timed-open circuitoperation, the cam surface 8b is in engagement with the cam follower 7and rotation of the actuating mechanism has stopped. The switch is in aclosed circuit position and the gap 24 between the gear sectors 12 and15 is positioned adjacent the driver pinion 10. The closed-circuitposition surface 8b of the cam 8 is wide enough to allow for additionalmanual rotation of the actuating mechanism without changing the switchposition. Also, the gap 24 is angularly arranged relative to the driverpinion 10 and the adjacent cam surfaces 8b and 8d to allow for manualrotation of the cam surface 8b or cam surface 8d into contact with thecam follower 7 without engaging the gear sectors and the driver pinion.

Manual-closed circuit operation, as illustrated in FIG. 1, is achievedmanually by rotating the set shaft counterclockwise through a smallangle after the end of the timed-open circuit drive-out sequence. Theadditional angular rotation causes the closed circuit detent 18 in theprojection 17 to engage the spring 16 supported between the base plates2a and 2b.

The cam follower 7 is maintained in engagement with the closed circuitposition surface 8b during the additional angular rotation necessary forengaging the spring in setting the timer at the manual-closed circuitposition.

The force of the spring 16 in the closed circuit detent 19 'releasablysecures the actuating mechanism from further Manual open-circuitoperation At the end of the timed-closed circuit operation, the

cam surface 8d is in engagement with the cam follower 7. The switch isin an open-circuit position and the gap 24 between the gear ysectors 12and 15 is positioned adjacent -the driver pinion 10. Additional angularrotation in a clockwise direction causes the projection 17 on the drivenmember 11 to engage the spring 16 within the open circuit detent 1S. Thecam follower 7 is maintained in engagement with the open circuitposition surface 8d during the additional angular -rotation necessaryfor engaging the spring in setting the timer at the manual open circuitposition. The force of the spring 16 in the open circuit detent 18releasably secures the set shaft from further rotation except bysubsequent manual rotation.

From the aforegoing discussion it will be apparent that the timermechanism of this invention provides for simple, single knob operationof a variety of timed and manual switch operations.

While a specific embodiment of this invention has been shown anddescribed, it is not intended that the invention be limited to theparticular structure shown and described and it is intended by theappended claims to cover all modifications within the spirit and scopeof this invention.

What is claimed is:

1. An interval -timer mechanism comprising:

(a) a unidirectional driver pinion;

(b) means driving said driver pinion;

(c) a bidirectional driven member having first and second gear sectors;

(d) said rst gear sector engaging said driver pinion on one side thereofto effect rotation of said driven member by said driver pinion in onedirection;

(e) said second gear sector engaging said driver pinion on the oppositeside thereof to effect rotation of said driven member by said driverpinion in the opposite direction, and

(f) a switch, means in operative engagement with and actuated by saiddriven member after a predetermined movement in one direction forclosing said switch and after a predetermined movement in the `oppositedirection for opening said switch.

2. An interval timer as recited in claim 1 wherein said driven membercomprises said external gear sector having external gear teeth thereon,a radially disposed arm angularly displaced from said external gearsector and extending to a greater radius than said external gear teeth,said arm having a circumferential extension therefrom with a pluralityof gear teeth on the internal face thereof comprising said internal gearsector, and said external gear sector being angularly spaced from saidinternal gear sector.

3. An interval timer as recited in claim 1 wherein said means -foropening and closing said switch comprises a cam actuated by said drivenmember, said cam comprising:

(a) a rst cam surface maintaining said switch open when said driverpinion engages said internal gear sector;

(b) a second cam surface maintaining said switch closed when saidinternal gear sector is driven out of engagement with said driverpinion;

(c) a third cam surface maintaining said switch closed when said driverpinion engages said external gear sector, and v (d) a fourth cam surfacemaintaining said switch open when said external gear sector is drivenout of engagement with said driver pinion.

4. An interval timer as recited in claim 3 including:

(a) a set shaft, said driven member being secured to said set shaft forrotation with said set shaft and said cam being floatingly mounted onsaid set shaft adjacent said driven member,

(b) a loose tongue and slot engagement between said cam and said drivenmember for enabling said driven member to rotate said cam,

(c) a cam follower engaging said cam for actuating said switch, said camfollower being biased against said cam to rapidly rotate said camthrough said loose tongue and slot engagement when said follower engagessaid cam between said first and second cam surfaces and said third andfourth cam surfaces, whereby said switch is rapidly actuated from anopen circuit position to a closed circuit position `and from a closedcircuit position to an open circuit position.

5. An interval timer comprising:

(a) a unidirectional driver pinion;

(b) means for driving said driver pinion;

(c) a bidirectional driven member having an internal gear sector and anexternal gear sector, said internal gear sector being angularly spacedfrom said external gear sector;

( d) said internal gear sector engaging said driver pinion on one sidethereof to effect rotation of said driven member by said driver pinionin one direction, and said external gear sector engaging said driverpinion the opposite side thereof to effect rotation of said drivenmember by said driver pinion in the opposite direction;

(e) a switch, switch actuation means in operative engagement with andactuated by said driven member after a predetermined movement in onedirection for closing said switch and after a predetermined movement inthe opposite direction for opening said switch;

(f) a radially projecting arm on said driven member having a first and asecond detent;

(g) spring means mounted between a pair of plates on said timer forengaging said first and second detents;

(h) manual means for rotating said driven member and said arm forpositioning said first and said second detents into and out ofengagement with said spring means;

(i) said switch actuation means comprising cam means, said cam meansbeing angularly arranged with said arm and said detents to maintain saidswitch open when said spring means engages said rst detent and tomaintain said switch closed when said spring means engages said seconddetent;

(j) said driven member being angularly arranged with said arm and saidcam means to maintain said gear sectors out of engagement with saiddriver pinion when said spring means engages said first and said seconddetents.

6. An interval 4timer comprising:

(a) a driver pinion;

(b) :unidirectional means for driving said driver pinion;

(c) a bidirectional driven member having external and internal gearsectors for engagement with said driver pinion, said external gearsector engaging said driver pinion on one side thereof for rotating saiddriven member in one direction and said internal gear sector engagingsaid driver pinion on the opposite side thereof for rotating said drivenmember in the opposite direction;

(d) `a switch, a cam mounted for rotation with said driven member foropening and closing said switch;

(e) said cam maintaining said switch closed when said external gearsector engages said driver pinion and said cam maintaining said switchopen when said internal gear sector engages said driver pinion;

(f) said cam actuating said switch from a closed to an open positionwhen said external gear sector is driven out of engagement with saiddriver pinion;

(g) said cam actuating said switch from an open t0 a closed positionwhen said internal gear sector is driven out of engagement with saiddriver pinion;

(h) manual means for 'rotating said cam for selectively opening andclosing said switch When said driver pinion is not in engagement withsaid gear sectors, and for selectively rotating said gear sectors intoengagement with said driver pinion.

. References Cited by theEXaminer UNITED STATES PATENTS Morrison 200-38X Morrison 200-38 Swayze 200--38 Holstein 200-35 Everard 200-38 Harris200--38 X l0 BERNARD A. GILHEANY, Primary Examiner.

H. M. FLECK, Assistant Examiner.

1. AN INTERVAL TIMER MECHANISM COMPRISING: (A) A UNIDIRECTIONAL DRIVERPINION; (B) MEANS DRIVING SAID DRIVER PINION; (C) A BIDIRECTIONAL DRIVENMEMBER HAVING FIRST AND SECOND GEAR SECTORS; (D) SAID FIRST GEAR SECTORENGAGING SAID DRIVER PINION ON ONE SIDE THEREOF TO EFFECT ROTATION OFSAID DRIVEN MEMBER BY SAID DRIVEN PINION IN ONE DIRECTION; (E) SAIDSECOND GEAR SECTOR ENGAGING SAID DRIVEN PINION ON THE OPPOSITE SIDETHEREOF TO EFFECT ROTATION OF SAID DRIVE MEMBER BY SAID DRIVER PINION INTHE OPPOSITE DIRECTION, AND (F) A SWITCH, MEANS IN OPERATIVE ENGAGEMENTWITH AND ACTUATED BY SAID DRIVEN MEMBER AFTER A PREDETERMINED MOVEMENTIN ONE DIRECTION FOR CLOSING SAID SWITCH AND AFTER A PREDETERMINEDMOVEMENT IN THE OPPOSITE DIRECTION FOR OPENING SAID SWITCH.